Disclosed is a sunshade device provided with a winding device; a screen capable of being pulled out of and housed in the winding device; a stay which comprises a body section and a pair of connection ends, and is installed at the pull-out end of the screen; and a pair of arms such that the tip ends are connected to the connection ends in such a way as to be capable of making relative rotation, that the base ends are supported by the winding device in such a manner as to be capable of making relative rotation, and that by rotational operation, attitudes can be changed between a folded attitude and a deployed attitude. Said pair of arms each comprise a rotational movement base section which has a first end portion that extends, in the deployed attitude, in the direction of a vertical frame and a second end portion that bends from the tip end of the first end portion and extends along the vertical frame; and an arm section which is connected to the second end portion and extends along the vertical frame in the deployed attitude. Each of said pair of connection ends is configured in such way as to be extensible and retractable in a state where force is applied extension-wise along the pull-out and housing direction of the screen.